This invention relates to a mobile communication apparatus for intermittently receiving a broadcasting signal at a reception timing which appears by a predetermined intermittent reception cycle.
For a standby period before occurrence of call reception or call origination (or call transmission) in a mobile communication apparatus (particularly in a mobile communication terminal) a broadcasting signal from a base station is intermittently received to save power consumption of a power supply battery. As is known in the art, the broadcasting signal includes control information of, for example, location registration control information. For example, Japanese Unexamined Patent Publication (JP-A) No. 252093/1993 discloses an intermittent reception system for a mobile communication apparatus. In the disclosed system, an intermittent reception cycle is set in an interval timer to be equal to a predetermined fixed value after the broadcasting signal from the base station has been securely subjected to a reception process for the first time by carrying out continuous reception of the broadcasting signal. Thereafter, the broadcasting signal is subjected to the reception process at every predetermined intermittent reception cycle thus determined. When the broadcasting signal from the base station can not be accurately subjected to the reception process in this event, the continuous reception is again performed so that the broadcasting signal from the base station is securely subjected to the reception process. It is noted here that the broadcasting signal from the base station can not be accurately subjected to the reception process mainly because the above-mentioned intermittent reception cycle is varied in compliance with temperature variation of an oscillation frequency of a low-frequency quartz oscillator for producing a clock pulse sequence counted by the interval timer.
In the above-mentioned conventional intermittent reception system, the continuous reception is performed again in case where the broadcasting signal from the base station can not be accurately subjected to the reception process, as described in the foregoing. Therefore, even during the standby period for call reception or call origination (transmission), the battery as a power supply of the mobile communication apparatus is exhausted at a greater ratio. This results in a disadvantage that a communicable time is shortened.